Electric heater.



W. A. RANKIN & W. M. HARWOOD.

ELEUTRIG HEATER.

APPLIGATIOH FILED 00123 1908 935,816. Patented Oct. 5. 1909.

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Witumu W. A. RANKIN 6: W. M. HARWOOD.

ELECTRIC HEATER.

APPLIOATXOH FILED OUT. 23, 1908.

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UNITED STATES PATENT OFFICE.

WILLIAM A. RANKIN AND WILLARD M. HARWOOD, F HUTCHINSON, KANSAS. AS-

SIGNOBS TO HARWOOD ELECTRIC HEATING CO.,

CORPORATION OF KANSAS.

0F HUTCHINSON. KANSAS. A

ELECTRIC HEATER.

Specification of Letters Patent.

Patented (lot. 5, 1909.

Application filed October 23, 1908. Serial No. 459,214.

l one of high resistance.

and Marian .\l. ll.\nwoon. hotl ritizens'ol' 3 the l lllltll States ol Ameriea. and residents of iluti-lnnson. in the eount} ot' lteno and State oi Kansas. have u'nente d rertaln new and useful Improvements in lilfit'tl'lC lit-at ers. of which the following is a sperilieatiou. This invention relates to certain new and useful in]prorements in eleetric heaters and.

make the heating element suparato from the tl(\'lt't' to he heated. and held in eontat't. therewith. In this form. part of the resistance not. living in intimate eontaet with the device to ho heated. is liahlo to become overheated as the heat from those parts has to be carried away hy transmission through the parts that are in eontaet or by radiation. thus some parts of the resistant-o are ororheattal and the lite ot' the element materially shortened.

The invention has for'its ohjeet-s among others to so arrange the resistanee that all parts of the eondurtor are in intimate eontaet with the part to he heated. for the purpose n'l seeurinL' the. rapid transmission of heat to the hotly to he heated. wherehyecon-v omy in eurrent ronsnmption is seeured and the danger ol m'erheating the resistant-e is eliminated.

t'urther ohjert of this invention is to so arrange the resistaure in tho slots. that a. helix is not formed around the metal to be heated. thereby eliminating induction or magnetie lag. \Ve endeavor to do this by plaeiug tho resistanee elements in grooves or slot s. While itis hest to have theseslots dirertly in the device, the fare oi which is to i do the work. when neeessary or d csired, they may he in a plate having a surlaee adapted to he lit-ought into intimate rontaetywith the derive to ho heatotl. i

The resist a nee elements are formed of an eleet riral romlurtin material, preferahly The are ot a form whorehy we get a lon; path of travel for the eurrent. and we are thus enahled to uso a. romluetor of great earryilureapat-ity in u romp-art spare. The way in \i'hieh we lune eoutemplated making the resistanee elements is in the form of a xigrzag grid or a flattened helix or wire formed in a zigzag manner. as shown in the attaehod drawings.

We do not intend to limit ourseh es to the exart form shown in the attached drawings. hut desire to use that one of the forms of resistance. mentioned above. as will best adapt itself to the partieular tleiiee being made. Xeither do we intend to limit ourselves to the exact form ol' slots shown. lt'here practical. they may be molded in or machined. or, in certain deviees. as. for oxamplu. a vessel in which to heat fluids. a sheet of metal may be hunted up leaving slots on one side to receive the resistance and grooves on the other side formimr a large area for the runtaet of the fluid. thus carrying tho heat away rapidly.

()thor ohjocts and adyantages of the invention will hereinafter appear and tho novel features thereof will he particularly pointed out in the appendd claims.

The invention is clearly illustrated in the accompanying drawings, which. with the numerals of reference marked thereon. form a part of this specification. and in whirlw- Figure 1 is a perspeetire view of a sad iron embodying our improvement. Fig. 3 is a top plan with the cover removed. Fig. 3 is a substantially central longitudinal section thronghthe eompleted iron with a. pm tion hroken away. the section heingg taken on the line 3-3 of Fig. 2.. Fig. 4 is an end olovation. Fig. 5 is a detail oi one of the Forms of zigzag grids that we may employ.

\Vo aim further to combine the resistanee with the hody to he heated in an improved manner whereby great elficiency is secured with a minimum expenditure of eurrent.

Like numerals of reference indicate like parts throughout the several views.

Referring to the drawings. 1 designates the body portion or bottom of the deviee. of whatewr nature it may he. in this instance shown as the hottom portion of a sad iron. having an integral raised portion 2. in whjeh raislal portion are a plurality of slots 3 adapted to receive the resistant-e element,

in the same slot, they are insulated from ,received within recesses 17 in the ends of a. 30

which, in this instance, we have chosen to show in the form of a zig-zag grid 4, being a flattened helix or wire formed in a zig-zag' manner, as shown best in Fig. 3, the'said grid being insulated from the walls of the slots by suitable insulating material 5. \Vhcre two layers of the resistance are placed each other by the insulation 6, as seen clearly in Fig. 4. In Fig. 2 the resistance element i is shown as with the breaks omitted. The bottom or body portion 1, in this instance, is shown as provided with a screw-threaded opening 7 which is adapted to receive a screw 8 having a head 9, said screw being passed through the cover 10 and through the raised portion 2 and en aging said opening to secure the cover fix ly in position to allow of its ready removal when desired. This cover is chambered upon itsunder side, as seen at 11, to receive the raised portion 2 of the body 1 and is ac arated from the latter by means of suitab e non-heat conducting material 12, as seen clearly in Fig.3.

13 and 14 are supports secured to the cover 10 by suitable means, as the screws 15, the upper ends of these supports having the por-. tions 16 which are para lel to each other and handle 18, the screw rod 19 serving to hold the handle and the said parallel portions of the supports in position, as seen clearly in Fig. 3. i In assembling the arts, the resistance element 4, together with the proper insulations 5 and 6, is embedded in theslots 8. One end of the resistance element is connected to the terminal 20 and the other end is secured to a like terminal '21 in the usual manner. These terminals are insulated from the cover by suitable insulating washer 22, as seen best in Fig. 3'. 7

In use, the electrical connections being made with the terminals in the usual mannor, the current passes through the resistance 4, and the heat. thus generated is ab sorbed by the bottom 'or body portion 1 as fast as generated, therefore the resistance material cannot be heated to a greater deso than the device to be heated and the ife of the device is therefore materially lengthened. It will be observed that, by the arrangement above described, in which the resistance element is formed of an electric conducting material of a high resistance and of a zi'g-zag form, that we obtain a-long ath of travel for the'current and thus are nabled to use a conductor of great car ing ehpaci in a small compact space whic in many orms of electrica 1y heated devices is Most essential. i I From the above it will be seen that we ihave deviscda simple, cheap,,dyet durable ,imd efiicient' electricheater, an {while the structural embodiment of the invention, as,

hereinbefore described, is what We at the present time consider preferable, it is evident that the same is subject to changes, variations and modifications without dc parting from the spirit of the invention or sacrificing any of its advantages. We therefore do not intend to restrict ourselves to the exact details, roportions of parts or other mechanical atures, but reserve the right to make such changes, variations and modifications as come properly within the scope of the protection prayed, as stated in the appended claims.

It IS evident that the zig-zag grid may be of different form; for instance in Fig. 5 we have shown one'form' 4 which consists of a thin strip or ribbon slotted or slitted on alternate sides so as to produce a long path of travel for the current; hence where in the following claims We refer to a zig-zag grid we wish to be understood as coverin all different forms of rid of such nature w are such increased pat for the current is provided.

What is claimed as new is 1. In a device of the character described, a body formed upon one side with an acting face and upon the opposite side with an integral raised portion with a series of slots formed therein, and a resistance element or elements in said slots and composed of a high resistance material of. zig-zag form.

2. In a device of the character described, a body formed upon one side with an acting face and 'upon the opposite side with an integral raised portion with a series of slots formed t-herein,-and a resistance element or elements in said slots and composed of a ribbon of resistance material, slotted on alternate sides to provide a relatively long path of travel for the current In-an electro-h'eated ap aratus,the combination of a metal plate ormed upon one side with an acting face and u on the 0 pcsite side with an integral rai portion aving a series, of slots, a resistance insulated from and embedded in said slots and arranged to readil radiate the heat generated to the metal p ate. 1

4. A resistance unit comprising a metal plate formed a on one side with an acting ace and upon t e op osite side with an in-' tegral raised portion viii a series of slots and adapted to be held in c ose contact with the device to be heated, and a resistance embedded in and insulated from said slots.

5. A resistance unit comprising a metal plate formed u on one side with an acting ace :and upon he opposite side with an integral raised rtion aving a series of slots, a resistance eg plant insulated from and arran (1 in saidslots no helix being formed on t e metal to be heated.

6, In an electric heater, a bod formed on one side with an acting face an on the op posite side with an integral raised portion having a multiplicity of slots, and a resist ance element in the form of a zig-zag grid disposed in said slots and suitably insulated therefrom, and a coyer havin :1 depending flanged portion secured over t e raised portion of the body.

7. In an electric heater, a body formed on one side with an acting face and on the op- Eosire side with an into red raised portion aving a multiplicity 0 slots, a resistance element in the forth of a zig-zag grid disposed in said slots and suitably insulated therefrom, a cover having a chambered portion to receive the raised portion of the body, non-heat conducting material separating said raised portion and cover, terminals haying their inner ends embedded in said material with an end of the resistance element secured to each, and means for detachabl y securing the cover to the body por tion.

8. In an electric heater, a body formed on one side with an acting face and on the opposite side with an integral raised portion with a multiplicity of slots and a zig-zag grid disposed in said slots, with two layers in each slot. said layers being insulated from each other and "from the walls of the slots.

9. In an electric heater, a body formed on one side with an acting face and on the opposite side with an integral raised portion witlra multiplicity of slots, a zig-zag grid disposed in said slots, with two layers in each slot, said layers being insulated from each other and from the walls of the slots, a chambered cover receiving said raised portion, it non-heat conducting material separating said raised portion and cover, means detnchnbly securing the cover to the body portion, and terminals carried by the cover and insulated therefrom.

Signed by us at Hutchinson, Kansas, this 17th day of ()ctoberl908.

WILLIAM A. RANKIN. WILLARD M. HARWOOD.

Vlitnesses:

H. J. Moss, G. M. VVILLIAMs. 

